Explanation:

2 and 3 only

Spacecraft: Purpose

Cassini-Huygens: Orbiting the Venus and transmitting data to the Earth (Incorrect)

Explanation: Cassini-Huygens was a spacecraft that orbited Saturn and its moon Titan, not Venus.

Cassini-Huygens: Orbiting the Venus and transmitting data to the Earth (Incorrect)

Explanation: Cassini-Huygens orbited Saturn and conducted detailed studies of the planet and its moons. It did not orbit Venus.

Messenger: Mapping and investigating Mercury (Correct)

Explanation: MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) was a NASA spacecraft that orbited Mercury, mapping its surface and studying its composition and magnetic field.

Voyager 1 and 2: Exploring the outer solar system (Correct)

Explanation: Voyager 1 and Voyager 2 were spacecraft launched to explore the outer solar system, including Jupiter, Saturn, Uranus, and Neptune.

Therefore, the correct answer is 2 and 3 only.